Makefile: `--target-arch amd64` is completely wrong

[xtaran]

Makefile contains this line:

dpkg-buildpackage -us -uc -b --target-arch amd64

This is wrong from multiple points of view:

• There is nothing architecture-dependent (it's a shell script after all!), so the package should be archicture all.
• The architecture is already specified via debian/control, not the commandline. Should be all, not any there, too.
• You don't know on which architecture the user will later use this script. Won't be installable on a Raspberry Pi which either has architecture armhf or arm64. The Architecture: any in debian/control already chooses the proper target architecture (the one of the host) by default, if you don't want to do cross-compiling for another architecture.

So please:

• Just drop the --target-arch amd64 from Makefile completely.
• Change Architecture: any to Architecture: all in debian/control.